Ministers have made a 'complete mess' of moves to introduce a 5p charge on carrier bags in England by making the scheme too complicated, MPs have warned.

The Government is planning to bring in a 5p charge on single-use plastic bags in England from next year to reduce the number handed out each year -an move pushed for by the Liberal Democrats.

But the Environmental Audit Committee said plans to exclude biodegradable bags, paper bags and small retailers from the scheme risk confusing consumers and undermining the effectiveness and benefits of the levy.

The 5p charge should be applied to all types of bags and retailers, a report by the parliamentary committee urged.

Lib Dem Norwich South MP Simon Wright, who is a member of the Select Committee which published the report, said: 'This is an issue that I, and many in Norwich, have been campaigning on for years.

'The scheme should be kept as straightforward as possible to encourage both retailers and their customers to re-use carrier bags and cut down on waste.'

Some eight billion single-use bags were handed out to consumers across the UK in 2012, but a 5p levy in Wales has shown significant success in reducing the number of carrier bags given out in the country by 75%.

The Environment Department (Defra) has proposed not to impose the charge on biodegradable bags, because it wants the industry to 'find innovative approaches to decrease the environmental impact of plastic bags'.

In addition, the 5p levy will not apply to paper bags or reusable plastic 'bags for life', and will not be charged in organisations of fewer than 250 employees.

Environmental Audit Committee (EAC) chair Joan Walley said: 'Ministers have managed to make a complete mess of their planned carrier bags charge by making it unnecessarily complicated.

'Carrier bags litter our streets and harm wildlife, and the Government is right to want to reduce their use.

'But Defra seems to have made decisions about the design of this scheme that were based more on wishful thinking than hard evidence.'

She added: 'Before the Government reaches the check-out with this policy, it needs to drop the exemptions and keep it simple to help shoppers do the right thing.

'This needn't be difficult - simple schemes in Wales and Ireland have dramatically reduced bag use, and had positive environmental impact. It's not too late to start listening and to re-think these flawed plans.'

A number of trade bodies representing smaller retailers oppose the exemption for companies with fewer than 250 employees, the EAC's report on the charge found.

The National Federation of Retail Newsagents, the Association of Convenience Stores and British Retail Consortium said the exemption would distort competition and cause confusion, and their members wanted to participate.

Small retailers should be included, but those with fewer than 10 employees should have reduced reporting requirements - as is the case in the Welsh scheme, the EAC's report said.

Paper bags can have greater carbon emissions than plastic carrier bags and leaving them out of the scheme undermines the 're-use' message and environmental benefits of cutting single use bags, the MPs said.

They should be included along with plastic bags, while the Government should also take steps to set a minimum price for bags for life that encourages their re-use, the report urged.

Leaving biodegradable bags out of the scheme could increase their use, potentially contaminating plastics recycling.

And they could still harm the environment by causing litter and damage to wildlife before they decay, the report warns.

The money raised through the charge will not be collected by the Government but businesses will be 'encouraged' to give it to charity.

The report welcomes the proposal that the money should go to charity, but it also urged the Government to spend the VAT raised on the charge - equal to almost 1p out of every 5p - on new environmental projects and monitoring the scheme.